The present invention relates to a vehicle power supply system.
As prior art vehicle power supply system, a power control apparatus, power supply abnormal condition detecting apparatus and vehicle brake system which are disclosed in JP-A-2001-114039 are known. This power control apparatus, power supply abnormal condition detecting apparatus and vehicle brake system are configured to connect an alternator, a main power supply apparatus including a main battery, and an auxiliary battery to a control apparatus including a brake ECU of an electric brake system an electric motor and the like via a main and auxiliary current supply lines for inputting voltages of the alternator, main power supply apparatus and part of a voltage of the main power supply apparatus input to the control apparatus to the power supply ECU as main power supply monitor signals. If there are inputs of the main power supply monitor signals, both the main power supply apparatus and the main current supply line are normal. If there is no input of the main power supply monitor signals although there is an input from the main power supply apparatus, and a signal representing no application of a voltage is generated, an abnormal condition of the main current supply line such as breaking thereof occurs. The auxiliary battery is connected to the control apparatus by closing a relay for this purpose for supplying a current.
Thus, a power supply control apparatus which is able to cope with the abnormal conditions of current supply lines, a power supply abnormal condition detecting apparatus and a vehicle brake system which is capable of coping with aforementioned abnormal conditions in both cases are provided.
If an abnormal condition occurs in the main current supply line in the above-mentioned prior art, the auxiliary battery is then connected to the control apparatus for supplying the control apparatus with a current. However, the prior art provides for taking no countermeasure if an abnormal condition occurs in, for example, a current supply line which connect the brake ECU with the electric motor.
It is an object of the present invention to provide a highly reliable vehicle power supply system which is capable of positively supplying an electric brake apparatus with necessary power even if an abnormal condition occurs in any one of all the conductors which are connected to a battery or an electric brake apparatus.
The above-mentioned object of the present invention is accomplished by providing connection switching means for connecting said auxiliary battery to any one of said plurality power supply lines. Since this allows at least one brake line of the electric brake apparatus to be positively supplied with power, necessary braking force can be generated.
The above-mentioned object of the present invention is accomplished by providing connection switching means for connecting said auxiliary battery to said main battery of at least one of said plurality power supply line. Since this allows at least one brake line of the electric brake apparatus to be positively supplied with power, necessary braking force can be generated.
The above-mentioned object of the present invention is accomplished by providing connection switching means for connecting said main battery to said plurality of power supply lines and for connecting said auxiliary battery to any one of said plurality power supply lines. Since this allows at least one brake line of the electric brake apparatus to be positively supplied with power, necessary braking force can be generated.
Preferably, diodes for preventing currents from flowing back to said main battery may be provided between said main battery and said plurality of power supply lines and a diode for preventing a current from flowing back to said connection switching means may be provided between said connection switching means and at least one of said power supply lines. Since this allows at least one brake line of the electric brake apparatus to be positively supplied with power, necessary braking force can be generated.
Preferably, connection of said auxiliary battery may be switched by said connection switching means in response to a current discharged from at least main and auxiliary batteries. Since this allows at least one brake line of the electric brake apparatus to be positively supplied with power, necessary braking force can be generated.
Preferably, connection of said auxiliary battery may be switched by said connection switching means in response to a current flowing through a conductor which is not provided with a diode of the conductors disposed between said connection switching means and said plurality of power supply lines, or a current flowing through a conductor disposed between said auxiliary battery and said connection switching means. Since this allows at least one brake line of the electric brake apparatus to be positively supplied with power, necessary braking force can be generated.